JP2005090901A - Energy supply system that effectively uses waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide energy that can not only effectively use waste as a fuel for boilers but also can further improve thermal efficiency by effectively using exhaust gas generated when drying waste as combustion air for waste boilers Provide a supply system.
An energy supply system that effectively uses waste M1, a prime mover 1 that generates power, a waste heat boiler 2 that generates steam using the exhaust gas of the prime mover 1 as a heat source, and a waste that uses the exhaust gas as a heat source A drying apparatus 3 for drying the product M1 and a waste combustion boiler 4 using the dried waste M2 as fuel are provided.
[Selection] Figure 1

Description

  The present invention is an energy that effectively uses wastes such as food production by-products such as coffee beans and tea husk that are produced in large quantities as a residue in food factories and sludge from sewage treatment plants as resources for boiler fuel. Regarding the supply system.

  Coffee beverage manufacturers such as coffee, Japanese tea, and oolong tea produce large amounts of residue such as coffee beans and tea leaves as food by-products. Until now, these food production by-products have not been effectively used as resources, and many of them have been incinerated as general industrial waste or disposed of in landfill after incineration reduction. However, the food production by-product contains a large amount of moisture and is not always easy to handle. Therefore, it has been desired to improve the handleability and effectively use it.

  For example, there are the following prior arts 1 and 2 as related techniques for meeting such a problem. In Prior Art 1, food waste such as unsold foods is dried with hot water using the heat of the exhaust gas from the exhaust heat boiler of the cogeneration system to reduce the amount, or the reduced amount is used as feed ( Patent Document 1).

Prior art 2 relates to the drying treatment of various wastes such as municipal waste, sewage sludge, industrial waste, livestock waste, etc., and uses high-temperature exhaust gas discharged from the exhaust heat boiler of the cogeneration system as the drying heat source. It is to try. As a result, the fuel cost required for drying the waste can be reduced (see Patent Document 2).
JP 2001-321740 A JP 2002-276915 A

  However, in the case of the prior art 1, the dried product is not expected to be used as boiler fuel, although it may be used as feed. Moreover, since the food is dried with warm water, the exhaust gas at the outlet of the warm water heat exchanger is not effectively used.

  In the case of the prior art 2, as in the prior art 1, the dried product is not assumed to be used as boiler fuel. Also, the exhaust gas at about 150 ° C. at the outlet of the drying device is not effectively used.

  Then, an object of this invention is to provide the energy supply system which can be effectively utilized as a fuel for waste combustion boilers, after drying waste using the heat | fever of the waste gas which came out of the exhaust heat boiler.

  In order to achieve the above object, an energy supply system that effectively uses waste according to one configuration of the present invention includes a prime mover that generates power, a waste heat boiler that generates steam using the exhaust gas of the prime mover as a heat source, and the exhaust gas. The apparatus includes a drying device that dries waste using the exhaust gas discharged from the heat boiler as a heat source, and a waste combustion boiler that uses the dried waste as fuel. Here, the production by-products come from food factories, such as food manufacturing residues such as tea husk and coffee beans, okara from tofu production, and seafood and vegetable fruit scraps generated from various canning factories. It includes food waste, and also includes industrial or domestic waste that contains a lot of water, such as sludge from sewage treatment plants.

  According to this configuration, the exhaust gas at a relatively high temperature (for example, about 150 ° C.) from the outlet of the exhaust heat boiler that has been exhausted to the atmosphere in the past is led to the drying device, and is effectively used for the drying treatment of waste containing a lot of moisture. Is done. The dried waste is effectively used as a fuel in a waste combustion boiler. Thereby, the fuel used with the boiler burner attached to a waste combustion boiler can be reduced. Thus, the high-temperature exhaust gas at the prime mover outlet is effectively used without waste, and the waste that has been dried is also effectively used as fuel in the waste combustion boiler, so that the thermal efficiency of the entire system is improved. Among the wastes, food waste is excellent as a fuel because it has a large amount of carbon (C) and generates a large amount of heat, and hardly contains heavy metals, so there are few problems of environmental pollution due to exhaust.

  In a preferred embodiment of the present invention, the exhaust gas after passing through the drying device is supplied to the waste combustion boiler as combustion air.

  According to this configuration, the exhaust gas after passing through the drying device is still high in temperature (for example, about 80 ° C.), and usually contains about 13 to 16% of residual air. Since this is high, by using this as combustion air in the waste combustion boiler, it is possible to further reduce the auxiliary combustion fuel in the burner attached to the waste combustion boiler. Moreover, even if odor is contained in the exhaust gas by the drying treatment in the drying device, the odor component can be thermally decomposed and reduced by high-temperature combustion in the waste combustion boiler, and odor to the surrounding environment. There is no risk of contamination.

  In a preferred embodiment of the present invention, a steam turbine driven by steam generated in the waste combustion boiler is further provided.

  According to this configuration, since the steam generated in the waste combustion boiler can be effectively used by the steam turbine, for example, by a method of driving a generator, energy efficiency is increased.

  In a preferred embodiment of the present invention, the prime mover is a gas turbine, and steam generated in the waste combustion boiler is supplied to a combustor of the gas turbine.

  According to this configuration, the steam generated in the waste combustion boiler is supplied to the combustor of the gas turbine as it is, not the steam generated by the external steam generating means, so that the output and thermal efficiency of the gas turbine are effective. Can be improved.

  In a preferred embodiment of the present invention, dry exhaust gas containing odor components discharged from the drying device is supplied to the prime mover as intake air.

  According to this configuration, the dry exhaust gas containing the odor component discharged from the drying device includes at least about 13 to 16% of the remaining air. Therefore, when this is used as the intake air in the prime mover, the intake to the prime mover is performed. The amount of air can be reduced and odor countermeasures to the surrounding environment can be achieved by thermal decomposition of the odor components. In the case where a deodorizing device is already installed, it is possible to reduce the fuel for deodorization in the deodorizing device by the processing in the prime mover.

  In a preferred embodiment of the present invention, a first generator driven by the prime mover is further provided.

  According to this configuration, waste heat from the prime mover is used for waste drying treatment, and the dried waste is effectively used as fuel in a waste combustion boiler to generate steam, and by the prime mover, Since the first generator is driven, an energy supply system with high overall efficiency can be obtained.

  In a preferred embodiment of the present invention, a second generator driven by the steam turbine is further provided.

  According to this configuration, since the second generator driven by the steam turbine is provided in addition to the first generator driven by the prime mover, a combined cycle system having high power generation efficiency can be obtained.

  An energy supply system that effectively uses waste according to another configuration of the present invention includes a prime mover that generates power, a waste heat boiler that generates steam using the exhaust gas of the prime mover as a heat source, and a waste that uses the exhaust gas as a heat source. A drying apparatus for drying the product, and a gasification melting boiler for steaming and baking the dried waste to generate pyrolysis gas and supplying it as fuel to the prime mover.

  According to this configuration, after the waste is dried, a pyrolysis gas is generated by, for example, dry distillation, that is, steaming in a gasification and melting boiler. Since this pyrolysis gas contains a large amount of carbon monoxide and hydrogen components, fuel such as heavy oil supplied to the prime mover can be reduced by supplying this to the prime mover as fuel. Cost can be reduced. Moreover, since the said waste baked with the gasification melting boiler is reduced significantly and handling property improves, it is easy to perform disposal by landfill.

  According to the energy supply system that effectively uses the waste of the present invention, the exhaust gas from the exhaust heat boiler can be used for drying waste such as coffee beans and tea leaves from a food factory that has been conventionally disposed of, The dried waste can be recovered as steam by putting it into a waste combustion boiler as a high calorie fuel. Alternatively, a pyrolysis gas is generated by a gasification melting boiler, and this gas is used as a fuel for a prime mover. Therefore, waste can be effectively used as a fuel resource.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing a combined cycle that is an energy supply system that effectively uses waste according to the first embodiment of the present invention. The system shown in FIG. 1 includes a gas turbine 1 as a prime mover, a waste heat boiler 2 attached thereto, and food production residues such as tea husks and coffee beans (hereinafter simply referred to as “waste”). This is basically composed of a drying device 3 that dries M1) and a waste combustion boiler 4 that uses the dried residue M2 as fuel.

  The gas turbine 1 includes a compressor C, a combustor FC, and a turbine T, and a first generator G1 that is a load is connected to a rotation shaft X1 thereof.

  An intake air cooler 5 is provided in the intake passage P1 for supplying the air A to the compressor C. The intake air cooler 5 cools the air A taken from the outside, for example, by circulation of groundwater W.

  The turbine T and the exhaust heat boiler 2 are connected by a turbine exhaust passage P <b> 2, and the exhaust gas EG from the turbine T is supplied to the exhaust heat boiler 2.

  An exhaust gas introduction passage P3 between the exhaust heat boiler 2 and the drying device 3 is provided with an economizer 6 and a three-way exhaust damper 7. The three-way exhaust damper 7 exhausts unnecessary exhaust gas EG into the atmosphere. A tower 8 is connected. The three-way exhaust damper 7 can supply the exhaust gas EG to the drying device 3 side by controlling the damper angle, or can flow to the exhaust tower 8 side and release to the atmosphere when the drying device 3 is stopped. Yes.

  Water in the boiler water supply tank 9 is pressurized by a water supply pump and supplied to the drum 10 of the exhaust heat boiler 2 through the economizer 6 through the water supply passage P4. The steam from the exhaust heat boiler 2 using the exhaust gas EG as a heat source passes through the drum 10 and a part thereof is supplied to the combustor FC of the gas turbine 1 through the gas turbine steam introduction passage P5. The other part of the steam becomes low-pressure steam through the pressure control valve 11, and then passes through the process steam passage P6 toward various steam consuming equipment, for example, a factory steam cleaner, a hot water generator, etc. Supplied as PS. Instead of being supplied as the process steam PS, it may be supplied to a steam turbine ST described later as indicated by a two-dot chain line P20.

  In the drying device 3, a residue M1 containing a large amount of water is batch-wise or continuously charged, and the residue M2 dried to a predetermined moisture content by the drying device 3 is As a high-calorie fuel, the waste-fired boiler 4 is fed batchwise or continuously. Here, the moisture content of the residue M1 is, for example, about 80%, and the moisture content of the residue M2 after drying is, for example, 7% or less.

                                                        Further, the outlet of the drying device 3 and the burner 41 attached to the waste combustion boiler 4 are connected by the combustion exhaust gas supply passage P7, and the exhaust gas EG at the outlet of the drying device 3 is connected to the burner 41 by the exhaust fan 12 provided in the passage P7. So that it can be used as part of the combustion air of the waste combustion boiler 4. The burner 41 is supplied with fuel f from the outside.

  On the other hand, the drying device 3 and the intake air cooler 5 are connected by a recovery passageway P8, and waste gas containing odor components generated during the drying process of the residue M1 during operation of the drying device 3 is taken into the intake air. The gas turbine 1 is sucked through the cooler 5. Thereby, since the said odor component is thermally decomposed by the gas turbine 1, it becomes a simple and effective odor countermeasure.

  The steam generated by the combustion of the residue M2 charged as the high calorie fuel in the waste combustion boiler 4 is supplied as a power source to the steam turbine ST via the steam supply path P9 for the steam turbine. The rotary shaft X2 of the steam turbine ST is connected to the second generator G2, and is used for power generation.

  Further, a discharge passage P10 for releasing the boiler exhaust BG from the waste combustion boiler 4 to the atmosphere is attached to the exhaust gas outlet of the waste combustion boiler 4, and dust in the boiler exhaust BG is put into the discharge passage P10. A multi-cyclone 14 for collecting and removing dust, an economizer 15, an air preheater 16, and an induction fan 17 for releasing boiler exhaust BG are provided. In the air preheater 16, the combustion air A1 taken in by the fan 18 is heated by the boiler exhaust BG and then sent to the burner 41 of the waste combustion boiler 4 through the air passage P11. The steam at the outlet of the steam turbine ST enters the water recovery passage P12 from the condenser 19 and is preheated by the economizer 15 and then returned to the drum 13 on the waste combustion boiler 4 side.

In the above configuration, the first generator G1 is driven by the gas turbine 1 to obtain electric power. When the gas turbine 1 is performing normal operation, the exhaust gas EG from the turbine T is supplied to the exhaust heat boiler 2 through the turbine exhaust passage P2 and recovered. On the other hand, the water pressurized by the water supply pump from the water supply tank 9 is preheated through the economizer 6 through the water supply passage P4, and then enters the drum 10 at the upper part of the exhaust heat boiler 2, from which the inside of the exhaust heat boiler 2 It enters the water pipe, is heated by the exhaust gas EG, and is vaporized. A part of the steam thus obtained is supplied to the combustor FC through the gas turbine steam introduction passage P5 through the drum 10 to improve the output and thermal efficiency of the gas turbine 1 and the NO _x in the exhaust gas EG. Reduction is realized. The other part of the steam from the drum 10 is supplied to an external user as the process steam PS via the process steam passage P6.

  The exhaust gas EG exiting the exhaust gas boiler 2 is guided to the drying device 3 through the exhaust gas introduction passage P3. At this time, the damper angle of the three-way exhaust damper 7 is adjusted to supply the drying device 3 while controlling the amount of exhaust gas. To do. As a result, the exhaust gas having a relatively high temperature (for example, about 150 ° C.) from the outlet of the exhaust heat boiler that has been discharged into the atmosphere in the past is guided to the drying device, and is effectively used for the drying treatment of waste containing a lot of moisture. When the drying device 3 is stopped, the entire amount of the exhaust gas EG is released from the exhaust pipe 8 to the atmosphere by damper control of the three-way exhaust damper 5. A predetermined amount of residue M1 (for example, moisture content of 80%) is fed into the drying apparatus 3 from above through a hopper or the like. The charged residue M1 is dried in the drying device 3 to become a residue M2 (for example, a moisture content of 7% or less).

  This residue M2 is put into the waste combustion boiler 4 as a dry high-calorie fuel. At the same time, the exhaust gas EG is supplied from the outlet of the drying device 3 through the combustion exhaust gas supply passage P7 to the burner 41 attached to the waste combustion boiler 4 by the exhaust fan 12. This exhaust gas EG becomes part of the combustion air of the waste combustion boiler 4 and is mixed with fuel f such as heavy oil and ignited at the burner outlet in the waste combustion boiler 4, and the burner flame BF Thus, the residue M2 is burned in the waste combustion boiler 4.

  Thus, by using the dried waste M2 as fuel, the fuel f used in the boiler burner 41 attached to the waste combustion boiler 4 can be reduced. Further, the exhaust gas EG after passing through the drying device 3 is still high in temperature (for example, about 80 ° C.) and usually contains about 13 to 16% of residual air, so the value as combustion air is high. By using this as combustion air in the waste combustion boiler 4, the auxiliary combustion fuel f in the burner attached to the waste combustion boiler 4 can be further reduced. Furthermore, even if the odor is contained in the exhaust gas EG by the drying process in the drying device 3, the odor component can be thermally decomposed and reduced by high-temperature combustion in the waste combustion boiler 4, and can be reduced to the surrounding environment. There is no risk of odor contamination. Moreover, the deodorizing apparatus for odor component processing becomes unnecessary, and when the deodorizing apparatus is already installed, the fuel for a deodorizing apparatus can be reduced.

  The steam generated in the waste combustion boiler 4 is supplied to the steam turbine ST through the steam supply passage P9 for the steam turbine, and drives the second generator G2. The steam leaving the steam turbine ST is returned from the condenser 19 to the drum 13 through the economizer 15 through the water recovery passage P12, and again used as boiler water.

  Thus, the high-temperature exhaust gas at the prime mover outlet is effectively used without waste in the drying device 3 and the waste combustion boiler 4, and the dried waste is also effectively used as fuel in the waste combustion boiler 4. , The thermal efficiency of the whole system is improved.

  The second embodiment shown in FIG. 2 is a cogeneration system in which the steam turbine ST is not incorporated in the energy supply system itself, unlike the combined cycle of the first embodiment in which power generation is performed by both the gas turbine and the steam turbine. . The basic configuration of the second embodiment is the same as that of the first embodiment. The description of the same parts is omitted, and only the differences are described. As shown in FIG. 2, the drum 13 on the waste combustion boiler 4 side and the first steam introduction passage P5 for the gas turbine are connected by the second steam introduction passage P13 for the gas turbine, and are generated in the waste combustion boiler 4. Steam can be injected into the combustor FC through the first and second introduction passages P13. The second steam introduction passage P13 is provided with a pressure adjusting valve 22 for matching the pressure of the first steam introduction passage P5. By setting it as such a structure, the output of the gas turbine 1 and a thermal efficiency are improved significantly.

  The third embodiment shown in FIG. 3 is also a cogeneration system similar to the second embodiment. The basic configuration of the third embodiment is the same as that of the first embodiment. The description of the same parts is omitted, and only the differences are described. As shown in FIG. 3, the waste combustion boiler 4 used in the first and second embodiments is abolished, and a gasification melting boiler 20 is used instead. The residue M2 is dry-distilled, that is, steamed and burned by the gasification melting boiler 20, and the generated pyrolysis gas is directly supplied to the combustor FC of the gas turbine 1 through the gas supply passage P14. Here, the pyrolysis gas can be a high calorie fuel containing a large amount of carbon monoxide and hydrogen. By supplying this pyrolysis gas to the combustor FC as a fuel, The amount of fuel such as heavy oil supplied to FC can be reduced. Further, in the third embodiment, the residue M2 can be significantly reduced by being baked in a steamed state, and the subsequent handling and disposal processing becomes extremely easy.

  The energy supply system that effectively uses the waste of the present invention is applied not only to food factories that produce a large amount of waste such as coffee beans and tea husk, but also to waste treatment at various power plants and garbage treatment facilities. It can be widely applied as a system for recycling and effectively utilizing waste as an energy resource in other similar processing facilities such as equipment.

1 is a system diagram showing an energy supply system that effectively uses waste according to a first embodiment of the present invention. It is a systematic diagram which shows the energy supply system which uses effectively the waste which concerns on 2nd Embodiment of this invention. It is a systematic diagram which shows the energy supply system which uses effectively the waste which concerns on 3rd Embodiment of this invention.

Explanation of symbols

1 Gas turbine (motor)
2 Waste heat boiler 3 Drying device 4 Waste combustion boiler 20 Gasification melting boiler FC Combustor G1 1st generator G2 2nd generator M1 Waste ST Steam turbine

Claims (8)

A prime mover generating power,
An exhaust heat boiler that generates steam using the exhaust gas of the prime mover as a heat source;
A drying device for drying waste using the exhaust gas from the exhaust heat boiler as a heat source;
A waste-fired boiler that uses dried waste as fuel,
Energy supply system with   The energy supply system according to claim 1, wherein the exhaust gas after passing through the drying device is supplied to the waste combustion boiler as combustion air.   3. The energy supply system according to claim 1, further comprising a steam turbine driven by steam generated in the waste combustion boiler.   4. The energy supply system according to claim 1, wherein the prime mover is a gas turbine, and steam generated in the waste combustion boiler is supplied to a combustor of the gas turbine.   5. The energy supply system according to claim 1, wherein dry exhaust gas containing odor components discharged from the drying device is supplied to the prime mover as intake air. 6.   6. The energy supply system according to claim 1, further comprising a first generator driven by the prime mover.   4. The energy supply system according to claim 3, further comprising a second generator driven by the steam turbine. A prime mover generating power,
An exhaust heat boiler that generates steam using the exhaust gas of the prime mover as a heat source;
A drying device for drying waste using the exhaust gas from the exhaust heat boiler as a heat source;
A gasification and melting boiler that steams the dried waste to generate pyrolysis gas and supplies it as fuel to the prime mover;
Energy supply system with

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